1. Field of the Invention
The present invention relates to an apparatus and a method of processing three-dimensional image data, and more particularly, to an apparatus and a method detecting an edge of three-dimensional image data.
2. Description of the Related Art
People perceive objects three-dimensionally. That is because people receive visual information about objects three-dimensionally through a sensory organ like eyes. A three-dimensional image process system has been developed for various fields for perceiving objects three-dimensionally as humans perceive objects using their eyes, and for displaying, as three-dimensional images for a user. For example, many problems have been solved by using a three-dimensional image process system in both medical and virtual reality fields.
For modeling three-dimensional objects in the three-dimensional image process system, efficiency of the system should be considered since considerable amounts of data are to be processed. Thus, the three-dimensional image process system performs a three-dimensional surface segmentation segmenting the object into meaningful areas through position information and depth information with regard to the three-dimensional image. Here, the meaningful area can be defined as an area having pixels with an equal value with regard to a certain characteristic. The three-dimensional surface segmentation can be realized through various image-processing methods. The most popularly used method is an image processing method grouping the area based on an edge of the three-dimensional image.
A method related to the edge detection of the three-dimensional image is introduced in “Edge detection in range images based on scan line approximation,” Computer Vision and Image Understanding. 73(2)/February 1999, pp.183˜199 by X. Jiang and H. Bunke.
In the above-mentioned method for edge detection of the three-dimensional image, a jump edge and a crease edge are detected through different processes to divide each object and area in the three-dimensional image. The jump edge has a discontinuous depth value generated when an object is overlapped with another object or a boundary point of a background and the crease edge has a discontinuous surface direction generated at a point where two surfaces different from each other meet.
However, in the conventional three-dimensional image processing method described above, the jump edge and the crease edge are detected through different processes, thus the three-dimensional image process is complicated.
Moreover, sometimes the crease edge is not detected completely, thus over-segmentation or under-segmentation might be performed. In other words, the edge of a two-dimensional intensity image is completely detected as the jump edge having the discontinuous depth value and thus easily detected by the edge detecting method based on a differential operator. However, the crease edge having the continuous depth value and the discontinuous surface direction in the three-dimensional image is not fully detected only by the differential operator.